This disclosure relates to containers, in particular, to containers for transportation and shipping.
Based on recent domestic and foreign events, governments and the commercial sector have become concerned with the potential importing and exporting of weapons of mass destruction by terrorists or other similar organizations. By accessing a standard shipping container, a weapon such as a nuclear weapon may be placed in the container and passed undetected through a port or other import/exporting facility.
In general, approximately sixteen million twenty foot containers are in use throughout the world. Additionally, approximately 40% of the personnel that load and off-load these containers come from nations that are on the terrorist list. Bribery and sabotage are common throughout the shipping industry, including government officials, shipping companies and freight forwarders. Large quantities of contraband material now pass through maritime commerce into many ports in the US.
Most containers, including, for example, 20 foot and 40 foot dry and hi-cube shipping containers currently entering the US are made of steel. Steel is a difficult medium to scan with X-rays, since considerable energy is required to penetrate a steel wall. Substantially less energy is required to penetrate a wall made of composite material. However, composite material is typically substantially more expensive than steel. It is possible to make a container entirely from composite materials or from composite panels welded to a steel frame. A potential advantage of a composite container is that it can be manufactured so as to embed sensor grids in the composite walls, with the result that it can detect intrusions through its sides as described in U.S. Patent Publication No. 2007/0229285 filed Oct. 4, 2007 and entitled “Secure panel with remotely controlled embedded devices.” However, primarily composite containers are typically substantially more expensive than a steel container.
Nuclear weapons contain fissile material. A nuclear weapon will emit radon gas and neutrons. Lead shielding will not shield radon gas and is a poor shield for neutrons. Currently available radon shielding involves an elaborate system of rubber and plastic seals. Only the United States Government has developed the technology to effectively shield radon from escaping from a nuclear weapon. It is very unlikely that a foreign adversary could produce a nuclear weapon that was shielded with lead so as to prevent the escape of gamma rays and also shielded so as to prevent the escape of radon gas and neutrons.